Contactless electronic tag

ABSTRACT

The contactless electronic device ( 12 ) comprising a near-field communication antenna ( 18 ), a microcircuit ( 20 ) connected to the antenna ( 18 ) and a magnetic shielding layer ( 24 ) arranged so as to extend substantially facing the antenna ( 18 ). The antenna ( 18 ) and the microcircuit ( 20 ) are combined into a module ( 26 ) and the device ( 12 ) comprises a body ( 16 ) comprising and open cavity ( 30 ) on one of its faces in which are housed the module and the shielding layer in such a way that the shielding layer closes off the cavity.

RELATED APPLICATIONS

This application claims the priority of French application no. 10/55888filed Jul. 20, 2010, the disclosure content of which is herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention relates to the technical field of electronic tagsof the contactless type. It applies more precisely but not exclusivelyto electronic tags intended to be affixed to the metal surface of anobject.

BACKGROUND OF THE INVENTION

By electronic tag is meant an assembly comprising a substrate, anear-field communication circuit comprising an electronic chip and anear-field communication antenna, allowing contactless communication tobe established with an external device for exchanging data. The antennais generally connected to the electronic chip and serves not only as ameans of contactless communication but also to produce the energy neededto feed the electronic chip.

In order to ensure optimal transmission of the data between the tag andthe external device regardless of the metallic environment of the tag,the tag is provided with a magnetic shielding layer capable ofprotecting the near-field communication circuit.

This is particularly advantageous, particularly for a “contactlesspayment” application embedded in a mobile telephone, the mobiletelephone including a battery and sometimes even a metal case which cangreatly harm the quality of data transmission to an outside reader whenthe tag is affixed to the telephone.

A contactless tag designed for application in a metallic environment isalready known in the state of the art, particularly from documentWO2008/065278. In this document, the tag includes an intermediate layermade of a magnetically hyperconducting material, placed against asubstrate bearing the antenna and the microcircuit. The assembly made upof the substrate, the antenna and the microcircuit is subsequentlyembedded in a cover made of plastic by lamination or casting.

The disadvantage of the tag thus obtained is that it remains relativelythick due to the presence, in addition to the substrate bearing theantenna and the microcircuit, of the intermediate layer and the cover.In addition, in this document, the dimensions of the tag are defined bythe dimensions of the antenna which extends over a relatively largesurface area.

There is at present a need for a customizable tag, of small thickness,of small dimensions and low manufacturing cost. In addition, this tagmust be designed to operate in a metallic environment such as forexample the vicinity of a mobile telephone.

SUMMARY OF THE INVENTION

One object of the invention is to provide a tag satisfying this need.

To this end, one aspect of the invention is directed to a contactlesselectronic device comprising a near-field communication antenna, amicrocircuit connected to the antenna and a magnetic shielding layerarranged to extend substantially facing the antenna. The antenna and themicrocircuit are combined into a module and the device includes a bodyhaving an open cavity on one of its faces in which are housed the moduleand the shielding layer such that the shielding layer closes off thecavity.

Due to the invention, the thickness of the tag is advantageouslyoptimized. Indeed, the shielding layer is housed in the same cavity asthe module and closes off this cavity. This double function of theshielding layer makes it possible to optimize the thickness of the tag.In addition, due to the fact that the antenna is incorporated into themodule, the length and the width of the tag can be substantially reducedto the effective surface of the antenna. The manufacture of such a tagis in addition relatively simple since all that is needed is to form acavity in a substrate layer and to incorporate the different functionalelements such as the antenna, the microcircuit and the shielding layer.

A device according to an embodiment of the invention can additionallyinclude one or another of the features in which:

-   -   the cavity includes a deep central area for housing the module        and a raised peripheral area surrounding the central area for        housing the shielding layer;    -   the cavity being provided with a peripheral wall and a bottom,        the wall includes an upper step separating the central area and        the peripheral area, to form an upper edge supporting the        shielding layer;    -   the cavity being provided with a peripheral wall and a bottom,        the wall includes, in the central area, a lower step separating        the first area housing the microcircuit from a second area for        housing a module substrate bearing the microcircuit and the        antenna, to form a lower edge supporting the module substrate;    -   the module includes a substrate bearing the microcircuit and the        antenna;    -   the body includes an electrically conductive ring substantially        surrounding en outside perimeter of the antenna and extending in        a plane parallel to a plane containing the antenna, or in the        same plane;    -   the device is a tag of the contactless type.

Another aspect of the invention is directed to a substrate for a tag ofthe contactless type comprising a body in the general shape of a plateand a small detachable plate constituting the tag, characterized inthat, the tag being one according to the invention, the cavity extendsinto the interior of the small plate.

A tag substrate according to an embodiment of the invention can alsoinclude the following features in which:

-   -   the small detachable plate is delimited by a breakable line made        in the substrate and designed to allow separation of the small        plate from the substrate by manual pressure alone;    -   the breakable line includes through perforations and/or blind        perforations;    -   the body including two small detachable plates constituting        first and second tags arranged side by side and facing in each        other.

Another aspect of the invention is directed to a manufacturing methodfor an electronic device including a near-field antenna and amicrocircuit connected to the antenna and a shielding layer extendingsubstantially facing the antenna, characterized in that a dimensionedcavity is formed to receive the module and the shielding layer, thecavity comprising a deep central area for housing the module and aperipheral area surrounding the deep central area for housing theshielding layer.

A method according to an embodiment of the invention can also includeone or another of the features in which:

-   -   the central area comprises a first central area provided with a        bottom for housing the microcircuit and a second peripheral area        raised with respect to the first central area delimiting a step        with a bottom for housing a substrate of the module bearing the        antenna and the microcircuit;    -   the cavity comprises three levels corresponding respectively to        a first peripheral area for housing the shielding layer, to a        second intermediate area for housing the subtitle of the module        bearing the antenna and the microcircuit and a third central        area housing the microcircuit.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will appear in the lightof the description that follows, made with reference to the appendeddrawings in which:

FIG. 1 shows a top view of a substrate for a contactless type tagaccording to a first embodiment of the invention;

FIG. 2 shows a section view along line 2-2 of the substrate of FIG. 1;

FIG. 3 shows a section view along line 2-2 of the device of FIG. 1,according to a second embodiment of the substrate of FIG. 1;

FIGS. 4 through 7 illustrate schematically the different manufacturingsteps of the device of FIG. 1;

FIG. 8 shows a top view of a substrate for a contactless type tagbearing two contactless type tags;

FIG. 9 shows a section view along line IX-IX of the substrate of FIG. 8;

FIG. 10 shows a mobile telephone bearing a contactless electronic tagforming a small detachable plate of the device of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Shown in FIG. 1 is an assembly comprising an electronic device accordingto a first embodiment of the invention and a substrate bearing theelectronic device. The assembly is designated by the general referencenumber 10, the electronic device is designated by the reference number12 and the substrate by the reference number 14.

In the example described, the device 12 is a contactless type electronictag. For example, the tag 12 comprises a body 16 with a thicknesssubstantially equal to 600 micrometers. The body 16 is for example madeof a plastic such as

PVC or even PC (polycarbonate), PE (polyethylene), etc. This body 16 ispreferably made by laminating together layers of plastic. For example,the body 16 is made by lamination of at least two layers made ofplastic, for example, and laminated together. In this first embodiment,the body 16 is formed in a single layer of plastic.

The tag 12 comprises, as illustrated in FIG. 2, a near-fieldcommunication antenna 18 and a microcircuit 20 connected to the antenna18 (shown dotted in FIG. 1). The microcircuit 20 and the antenna 18together constitute near-field communication means capable ofcommunicating with external equipment such as a specialized reader. Forexample, the near-field communication means 22 of the tag 12 and thereader are able to communicate in compliance with the ISO 14443communication protocol.

The antenna 18 consists for example of a plurality of electricallyconductive coils and delimits an effective surface S for receiving amagnetic field. By effective surface S is meant, for the purposes of theinvention, the surface area of the antenna 18 which, when traversed by amagnetic field, produces an induced current circulating in the antenna18. This effective surface S is in this example delimited by the outsideperimeter of the antenna 18. In addition, in this example, the antenna18 is made up of two parts 18A, 18B.

In addition, the tag 12 includes a magnetic shielding layer 24 arrangedto extend at least partly facing the surface S of the antenna 18. Such alayer 24 makes it possible in particular to reduce the magneticdisturbances generated by a metallic environment situated in proximityto the tag 12. The layer 24 is made for example of an electricallyinsulating and magnetically permeable material such as ferrite forexample. The thickness of the layer is comprised for example between 100and 300 micrometers and its relative permeability is roughly 100.

Preferably, the layer 24 has dimensions slightly greater than thesurface S of the antenna 18 and is arranged in the tag 12 so as to coverits entire surface S.

More particularly and in conformity with the invention, the antenna 18and the microcircuit 20 are combined in a single module 26 illustratedin detail in FIG. 4A or FIG. 4B. Preferably, this module 26 comprises asubstrate 28 bearing the microcircuit 20 and the antenna 18. Forexample, the substrate 28 is delimited by first 28A and second 28Bopposite faces, one of the faces bearing the microcircuit 20 and atleast part of the antenna 18, the antenna 18 possibly consisting of twoparts 18A, 18B extending on each of the faces 28A, 28B of the substrate28 as illustrated in FIG. 2.

In the example illustrated in FIG. 4A, the microcircuit 20 is assembledby means of wire contacts, the microcircuit 20 being encapsulated in apolymer resin shell 21. This process is called “wire bonding.” In avariation illustrated by FIG. 4B, the microcircuit 20 is assembled onthe substrate 28 by means of a chip transfer process, the microcircuit20 being said in this case to be “flip-chip” mounted.

More precisely, the tag 12 comprises an open cavity 30 on one of thefaces 16A, 16B of the body 16 of the tag 12. Inside this cavity 30 arehoused the module 26 and the shielding layer 24 in such a way that theshielding layer 24 closes off the cavity 30.

Thus the module 26 is entirely incorporated into the body 16 of the tag12 and can not be extracted without removing the shielding layer 24which closes off this cavity 30 and hides the module 26 in the body 16of the tag 12.

Preferably, the cavity 30 being delimited by a peripheral wall 32 and abottom 34, the cavity 30 includes a central area for housing the moduleand a peripheral area 38 surrounding the central area 36 for housing theshielding layer 24.

As illustrated in FIG. 2, the peripheral region 38 is sized tocompletely receive the shielding layer 24.

In addition, the wall 32 preferably includes an upper step 40 separatingthe central area 36 and the peripheral area 38 to form an upper edge 41supporting the shielding layer 24.

In the example described, the central area 36 is itself made of twodistinct areas, a first central area 42 for housing the microcircuit 20and a second peripheral area 44 for housing the substrate 28 of themodule 26. The central area 36 preferably includes a lower step 46 forforming a lower edge 48 supporting the substrate 28 of the module 25bearing the microcircuit 20 and the antenna 18. Thus, the lower step 46delimits with the bottom 34 of the cavity 30 a deep area 42 for housingthe microcircuit 20.

Preferably, as illustrated in FIGS. 1 and 2, the contactless type tag 12forms a detachable plate of the contactless tag substrate 14. In theexample described, the substrate 14 is made of a plastic identical tothat constituting the body 16 of the tag 12, the tag 12 and thesubstrate 14 being drawn from the same stock. For example, the substrate14 is made by lamination of at least two layers made of a plastic, forexample, and laminated together.

In a preferred embodiment of the invention (illustrated in FIG. 1), thesubstrate 14 delimits outside dimensions compliant with a standardmicrocircuit card format, for example the ID-1 format of the ISO 7816standard. Preferably, however, the card has a thickness less than the800 micrometers compliant with the ISO 7816 standard. AS a variation,the thickness can be about 600 micrometers.

For example, the small plate constituting the tag 12 is delimited by abreakable line 50, provided in the substrate 14 and arranged to allowseparation of the small plate 12 and the substrate 14 by manual pressurealone along this line 50. For example, the line 50 includes throughperforations 52 and/or blind perforations 54. In the exampleillustrated, the small plate 12 has a substantially rectangular generalshape and through perforations 52 are made along the short lateral edgesand blind perforations 54 are made along the long lateral edges of therectangle forming the small plate.

In the embodiment of the invention, the tag 12 has dimensions of about15 mm×30 mm for example, possibly 30 mm×20 mm.

In the example illustrated and by preference, the peripheral area 38 ofthe cavity 30 extends at least through the entire small plate 12, forexample extending to either side of the periphery of the small plate 12.Thus, the breakable line 50 extends partly on the shielding layer 24 andthis line 50 includes at least one perforation running through thethickness of the shielding layer 24.

In addition, by preference, the shielding layer 24 includes a first face24A to be oriented toward the outside of the cavity 30, a first adhesivecoating to allow the detachable small plate to be transferred to asurface of an external piece of equipment by adhesion, is flush with thesurface of the substrate. Preferably, this first adhesive coating isprovided with a removable non-adhesive foil to facilitate the handlingof the device and avoid the accumulation of dust and particles on theadhesive coating.

Further, the shielding layer 24 includes a second face 24B to beoriented toward the inside of the cavity 30. This face 24B includes forexample a second adhesive coating such that the layer 24 can betransferred by adhesion into the cavity 30.

The small plate, once detached, constitutes a contactless electronic tag12 having a reading face 12B from which data can be exchanged betweenthe near-field communication means and an external reader and ashielding face 12A capable of limiting all the interference that can begenerated by an object onto which the tag is affixed.

For example, the small detachable plate or the contactless typeelectronic tag incorporates an electronic payment function and isintended to be transferred by adhesion onto a mobile telephone terminal60, as illustrated in FIG. 10. In particular, it can be seen in thisfigure that the tag 12 is stuck to the back of this telephone.

Also shown in FIGS. 8 and 9 is another embodiment of the tag substratein which two contactless type tags can be placed.

The substrate 14 comprises a card body with at least the first 64 andsecond 66 electronic tags. The tags respectively comprise the first andsecond transponder assemblies capable of being activated by theapplication of a magnetic field.

Preferably, these electronic tags are set side by side along alongitudinal direction of the card body and facing each other. In thiscase, the substrate is provided with a weakening line 62 separating twoareas Z1, Z2 each bearing one of the electronic tags 64, 66. Thisweakening line comprises for example two blind perforations with a “U”shape in profile made in both faces of the card substrate opposite oneanother. The tags are also arranged facing one another and cavities areformed on each of the opposite faces in such a way that the tags arearranged with opposite orientations.

This face-to-face arrangement of the tags also has the advantage ofpreventing the application of a magnetic field to one of the faces ofthe substrate from causing the activation of both transponderassemblies, particularly in the case of a customization.

A second embodiment of the device according to the invention is shown inFIG. 3. In this figure, equivalent elements are designated by identicalreference numbers.

In this second embodiment, the tag 12 also includes an electricallyconductive ring 70, constituting a means of amplifying the gain of theantenna 18, which extends around an outside perimeter of the antenna 18in the same plane as the latter or, as illustrated in FIG. 3, in a planeparallel to the plane containing at least part of the antenna 18A or18B.

Thus, the ring 70 consists for example of a deposit of electricallyconductive ink on one face of one of the layers constituting the body 16of the tag 12. Preferably, in this case, the body 16 of the tag 12consists of at least two layers of plastic. In addition, in this case,the ring 70 is preferably set straddling the breakable line 50delimiting the outside perimeter of the small plate so that the width ofthe ring is maximized by extending it as close as possible to theoutside perimeter of the small detachable plate.

The principal steps of a manufacturing method for the assembly 10according to the second embodiment of the invention will now bedescribed with reference to FIGS. 5 through 7.

First, the card body constituting the substrate of the tag is made, forexample by laminating together a plurality of layers. For example, atleast two layers are laminated so as to obtain a card body with athickness less than or qual to 600 micrometers. In addition, asillustrated in FIG. 5, a ring 70 of electrically conductive ink ispreferably deposited on one of the faces of one of the layers so thatthis ring can surround the module once the latter is housed in the tag.

Then the method comprises a step of machining a cavity in the card body20. A location Z for the small detachable plate 12 is preferably definedbeforehand, and the cavity 30 is machined in that location Z.

Such a cavity is generally obtained by machining, typically by millingor spot facing in three continuously executed operations:

-   -   a large spot facing operation to form the peripheral area 38,    -   a medium spot facing operation to form the intermediate area 44,    -   a small spot facing operation to form the deeper central area        42.

Thus the cavity is made in a single spot facing operation, the spotfacing tool moving to form the different steps.

Then the method comprises a step of housing the module 26 in the cavity30 (FIG. 5) in such a way that the substrate 28 of the module 26 restson the inner peripheral edge 48 surrounding the deep area 42, and a stepof housing the magnetic shielding layer 24 within the cavity 30 asillustrated in FIG. 6: preferably, this shielding layer 24 istransferred by adhesion to the inside of the cavity 30. In addition, theshielding layer 24 includes, on the face opposite to that glued to thebottom of the cavity, the adhesive coating provided with a removableanti-adhesive foil.

Finally, the method comprises a step of pre-cutting of the small platealong the boundaries defined by the location Z to form the small platedetachable from the substrate as illustrated in FIG. 7. In the preferredembodiment of the invention, this pre-cutting step consists of forming abreakable line 50 allowing separation of the small plate from the bodyby manual pressure alone.

Thanks to the invention, due to the fact that the shielding layer 24 isincorporated into a substrate and that the transponder assembly is alsoincorporated into the same cavity as the shielding layer, the thicknessof the substrate can be relatively reduced.

The invention claimed is:
 1. A contactless electronic device (12)comprising a near-field communication antenna (18), a microcircuit (20)connected to the antenna (18) and a magnetic shielding layer (24)arranged so as to extend substantially facing the antenna (18), whereinthe antenna (18) and the microcircuit (20) are combined into a module(26), and wherein the device (12) comprises a body (16) comprising anopen cavity (30) on one of its faces in which are housed the module (26)and the shielding layer (24) so that the shielding layer (24) closes offthe cavity (30).
 2. The device (12) according to claim 1, wherein thecavity (30) comprises a deep central area (36) for housing the module(26) and a raised peripheral area (38) surrounding the central area (36)for housing the shielding layer (24).
 3. The device (12) according toclaim 2, wherein the cavity (30) is provided with a peripheral wall (32)and a bottom (34), the wall (32) comprises an upper step (38) separatingthe central area (36) and the peripheral area (38) to form an upper edge(41) supporting the shielding layer (24).
 4. The device (12) accordingto claim 2, wherein the cavity (30) being provided with a peripheralwall (32) and a bottom (34), the wall comprises, in the central area, alower step (46), separating a first area (42) for housing themicrocircuit (20) and a second area (44) for housing a module (26)substrate (28) bearing the microcircuit (20) and the antenna (18), toform a lower edge (48) supporting the module (26) substrate (28).
 5. Thedevice (12) according to claim 1, wherein the module comprises asubstrate bearing the microcircuit (20) and the antenna (18).
 6. Thedevice (12) according to claim 1, wherein the body includes anelectrically conductive ring (70) substantially surrounding an outsideperimeter of the antenna (18) and extending within a plane parallel to aplane containing the antenna (18) or in the same plane.
 7. The device(12) according to claim 1, being a contactless type tag.
 8. A substrate(14) for a contactless type tag (12), comprising a body in the generalshape of a plate and a small detachable plate (12) constituting the tag,wherein, the tag (12) being a device according to claim 1, the cavityextends into the small plate.
 9. The substrate (12) according to claim8, wherein the small detachable plate (12) is delimited by a breakableline (50) provided in the substrate (14) and designed to allowseparation of the small wafer (12) from the substrate (14) by manualpressure alone.
 10. The substrate (14) according to claim 9, wherein thebreakable line (50) comprises through perforations (52) and/or blindperforations (54).
 11. The substrate (14) according to claim 8, the bodyof the substrate (12) including two small detachable plates (12A, 12B)constituting the first and second tags arranged side by side along alongitudinal direction of the substrate (14), and facing each other. 12.A method for manufacturing an electronic device (12) comprising anear-field communication antenna (18) and a microcircuit (20) connectedto the antenna (18), the antenna (18) and the microcircuit (20) beingcombined in a module (26), and a shielding layer (24) extendingsubstantially facing the antenna (18), wherein a cavity (30) is made,sized to receive the module (26) and the shielding layer (24), thecavity (30) comprising a deep central area for housing the module (26)and a peripheral area surrounding the central area for housing theshielding layer (24).
 13. The method according to claim 12, wherein thecentral area (36) comprises a first central area (42) provided with abottom (34) for housing the microcircuit (20) and a second peripheralarea (44), raised with respect to the first central area (42),delimiting a step (46) with the bottom (34) for housing a substrate (28)of the module (26) bearing the antenna (18) and the microcircuit (20).14. The method according to claim 12, wherein the cavity (30) comprisesthree levels corresponding respectively to a first peripheral area (38)for housing the shielding layer (24), to a second intermediate area (44)for housing a module (26) substrate (28) bearing the antenna (18) andthe microcircuit (20) and to a third central area (46) for housing themicrocircuit (20).